Renesis OIL PRESSURE Discussion with Dealer Tech
10-08-2009, 11:30 AM
#202
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Sitting idling is not a good way of warming an engine up, there's not enough heat to thin the oil out quick enough, you need a balance - light throttle openings and 2-3krpm until the oil is warmed through.
10-11-2009, 07:08 AM
#203
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Interesting thread!
While I'm not an expert, I would like to clarify any confusion regarding how pressure and flow of a fluid is interrelated. So, I went ahead and drew up a crappy image showing a fluid (lets just say oil) pump with a series of 3 different diameter passages. We can pretend that the pump has an infinite source of oil going to it, and the end of passage C lets the oil spill all over the floor.
Lets say that we take two separate measurements of oil flow through passage A; the first one with a working pressure of 50psi, and the other at 100psi. At 100psi, the flow through passage a will be double that of 50psi. I'm sure we all know that already. Ok, now lets take a look at passage B; it's smaller than both passage A and C. What's my point? If we want the oil through passage C to fill it's entire volume while flowing, there will need to be some minimum pressure in passage A to maintain it. Too low a pressure, and only a small stream might be flowing through C (nevermind A and B).
Now lets try to use our imagination a little bit, and try to imagine the image as such:
The oil pump is, well, the engine oil pump
Passage A is an oil passage leading to a bearing journal
Passage B is the bearing journal
Passage C is the space between the bearing and a shaft
With that said, our goal is to ensure that the gap between the bearing and shaft is filled with oil. In order to do that, we need to make sure enough oil flows through the bearing journal. In order to ensure enough flow through the journal, there needs to be enough pressure in the passage way. The amount of pressure necessary to achieve this is dictated by the size of the journal, and the total area between the shaft/bearing that needs to be filled with oil. Also, keep in mind, oil is constantly flowing OUT of the area too, where it finally ends up in the oil pan.
So, when taking a look at the oil between the rotor and e-shaft, we need to make sure enough oil is FLOWING in order to prevent metal to metal contact. But in order to make sure enough oil is FLOWING, the PRESSURE in the oil passages need to be at some minimum pressure. The minimum pressure is different for various engines, and thus, needs to be determined at design time. 30psi could certainly be sufficient, but then again, it might not be - most likely, it's only the mazda engineers that know precisely.
So to say that only pressure, or flow, or oil presence is all that matters is a bit misleading, as they're all interrelated, and you can't have one without the other. Hopefully this makes sense, and is able to help some of you out.
Once we finally get the oil in the bearing, we don't want it to shear. Heavier weight oil usually ensures this. However, there is a point where the oil becomes too thick to adequately flow within the confines of the bearing without requiring too much working pressure/flow (and thus, engine power). Luckily, even very high performance engines don't use more than 60-weight anyways.
It would be nice to see an oil analysis report from a large group of renesis owners with various oil weights as well. I imagine that 5w-20 had to break down to the point where it was basically dirty water. It wouldn't be hard to see why there would be massive bearing failures.
While I'm not an expert, I would like to clarify any confusion regarding how pressure and flow of a fluid is interrelated. So, I went ahead and drew up a crappy image showing a fluid (lets just say oil) pump with a series of 3 different diameter passages. We can pretend that the pump has an infinite source of oil going to it, and the end of passage C lets the oil spill all over the floor.
Lets say that we take two separate measurements of oil flow through passage A; the first one with a working pressure of 50psi, and the other at 100psi. At 100psi, the flow through passage a will be double that of 50psi. I'm sure we all know that already. Ok, now lets take a look at passage B; it's smaller than both passage A and C. What's my point? If we want the oil through passage C to fill it's entire volume while flowing, there will need to be some minimum pressure in passage A to maintain it. Too low a pressure, and only a small stream might be flowing through C (nevermind A and B).
Now lets try to use our imagination a little bit, and try to imagine the image as such:
The oil pump is, well, the engine oil pump
Passage A is an oil passage leading to a bearing journal
Passage B is the bearing journal
Passage C is the space between the bearing and a shaft
With that said, our goal is to ensure that the gap between the bearing and shaft is filled with oil. In order to do that, we need to make sure enough oil flows through the bearing journal. In order to ensure enough flow through the journal, there needs to be enough pressure in the passage way. The amount of pressure necessary to achieve this is dictated by the size of the journal, and the total area between the shaft/bearing that needs to be filled with oil. Also, keep in mind, oil is constantly flowing OUT of the area too, where it finally ends up in the oil pan.
So, when taking a look at the oil between the rotor and e-shaft, we need to make sure enough oil is FLOWING in order to prevent metal to metal contact. But in order to make sure enough oil is FLOWING, the PRESSURE in the oil passages need to be at some minimum pressure. The minimum pressure is different for various engines, and thus, needs to be determined at design time. 30psi could certainly be sufficient, but then again, it might not be - most likely, it's only the mazda engineers that know precisely.
So to say that only pressure, or flow, or oil presence is all that matters is a bit misleading, as they're all interrelated, and you can't have one without the other. Hopefully this makes sense, and is able to help some of you out.
Once we finally get the oil in the bearing, we don't want it to shear. Heavier weight oil usually ensures this. However, there is a point where the oil becomes too thick to adequately flow within the confines of the bearing without requiring too much working pressure/flow (and thus, engine power). Luckily, even very high performance engines don't use more than 60-weight anyways.
It would be nice to see an oil analysis report from a large group of renesis owners with various oil weights as well. I imagine that 5w-20 had to break down to the point where it was basically dirty water. It wouldn't be hard to see why there would be massive bearing failures.
10-11-2009, 07:52 AM
#204
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Just read through the first section of the article posted @ http://ferrarichat.com/forum/showthread.php?t=136052 and have found a bit of contradiction.
The writer claims "If your engine is running hot use a thinner oil.", he then says that in hot climates, his ferrari manual recommends 10w-60 in hot climates under racing conditions, and 0w-40 in cooler climates and city driving.
I'm not sure how much more of this guy's crap I'm willing to read.
The writer claims "If your engine is running hot use a thinner oil.", he then says that in hot climates, his ferrari manual recommends 10w-60 in hot climates under racing conditions, and 0w-40 in cooler climates and city driving.
I'm not sure how much more of this guy's crap I'm willing to read.
10-11-2009, 08:01 AM
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Oh, and lastly, just another factor for the OP's question of "what has changed" between older rotaries and the renesis. While it appears that there are a lot of the same parts, an obvious difference is power output. Couple higher working pressures during the combustion phase with lower viscosity oils, and you have a potential recipe for disaster that didn't exist in previous N/A rotaries.
ASH, what kind of similarities do we see see between oil system related parts in the 13b-msp and the the 13b-rew?
ASH, what kind of similarities do we see see between oil system related parts in the 13b-msp and the the 13b-rew?
10-11-2009, 01:44 PM
#206
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Just to throw a bit of information out there. Back in the late 60's when the rotary program was pretty young, Mazda immediately started racing the rotary trying to prove it's durablity. In one of the 24 hour races they entered back then, I think it was a Spa Francorchamps from one of those years, their car developed a split in the oil cooler about halfway through the race. The cooler was made of copper and apparently a braze joint had failed. They couldn't get it fixed but they could bypass it completely. They did. They drained the oil and ran the rest of the race on a thicker oil. It worked. Not optimal but it worked.
10-11-2009, 03:42 PM
#207
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Thread Starter
ASH, what kind of similarities do we see see between oil system related parts in the 13b-msp and the the 13b-rew?
The only difference to the FE1031 RX-8 (S1) are the OIL Pump 'Rotors' by Part Number, but they use the same oil pump shaft as the RX-8 S1 and FC, same oil pump chain, mounting bolts, etc, so I am pretty sure the FD pump would fit on the S1 RX-8, the actual design of all these components are the same.
I don't have an FD Service manual to check/compare the Oil Pump's PSI pressure.
Even the FD uses the same BY Pass Plunger (0221-14-115) as the RX-8 S1, EPC shows the spring but NO Corresponding Part Number?, I am assuming it is 0221-14-116, but it may not be.
As we know the FC RX-7 which is the originator of N326 model code for Mazda Part Number uses the exact same Oil Pump and Valves in the FE1031 RX-8. The FE1032 RX-8 (S2) has an all new high pressure oil pump, but even the oil pump chain is the same as all rotaries from the FC.
As I have said before even the FD uses the same SG Bearings, Including Rotor Bearings as the RX-8.
10-11-2009, 05:37 PM
#208
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From the Oil Pumping aspect, for all FD RX-7's the oil pump parts were the same.
The only difference to the FE1031 RX-8 (S1) are the OIL Pump 'Rotors' by Part Number, but they use the same oil pump shaft as the RX-8 S1 and FC, same oil pump chain, mounting bolts, etc, so I am pretty sure the FD pump would fit on the S1 RX-8, the actual design of all these components are the same.
I don't have an FD Service manual to check/compare the Oil Pump's PSI pressure.
Even the FD uses the same BY Pass Plunger (0221-14-115) as the RX-8 S1, EPC shows the spring but NO Corresponding Part Number?, I am assuming it is 0221-14-116, but it may not be.
As we know the FC RX-7 which is the originator of N326 model code for Mazda Part Number uses the exact same Oil Pump and Valves in the FE1031 RX-8. The FE1032 RX-8 (S2) has an all new high pressure oil pump, but even the oil pump chain is the same as all rotaries from the FC.
As I have said before even the FD uses the same SG Bearings, Including Rotor Bearings as the RX-8.
The only difference to the FE1031 RX-8 (S1) are the OIL Pump 'Rotors' by Part Number, but they use the same oil pump shaft as the RX-8 S1 and FC, same oil pump chain, mounting bolts, etc, so I am pretty sure the FD pump would fit on the S1 RX-8, the actual design of all these components are the same.
I don't have an FD Service manual to check/compare the Oil Pump's PSI pressure.
Even the FD uses the same BY Pass Plunger (0221-14-115) as the RX-8 S1, EPC shows the spring but NO Corresponding Part Number?, I am assuming it is 0221-14-116, but it may not be.
As we know the FC RX-7 which is the originator of N326 model code for Mazda Part Number uses the exact same Oil Pump and Valves in the FE1031 RX-8. The FE1032 RX-8 (S2) has an all new high pressure oil pump, but even the oil pump chain is the same as all rotaries from the FC.
As I have said before even the FD uses the same SG Bearings, Including Rotor Bearings as the RX-8.
Good info... What kind of oil are the majority of the FD guys using?
10-11-2009, 06:02 PM
#209
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Thread Starter
On Castrol Australia's website a 15W40 is recommended....not sure what the factory manual says, I think it would be around this mark.
This was the grade we used at our Mazda dealership when the FD was out.
This was the grade we used at our Mazda dealership when the FD was out.
10-12-2009, 01:12 AM
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10-12-2009, 01:33 AM
#215
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If you're just moving the car, like pulling it out of the garage to wash it, then you'd be better off driving it around the block rather than letting it idle til warm.
Ken
10-12-2009, 08:49 AM
#216
Momentum Keeps Me Going
My 3c worth. After reading thru this entire thread, it's obvious there's a lot of info info here sort of distilled from so many threads before. Still, much here is based on speculation or 'assumptions' about oil and how it works, plus a little bit of comment based on actual experience and tear down. But strangely as far as I saw only a couple people mention (or comment on) the importance of the intrinsic quality of an oil to start off with.
This factor of basic importance is one shrouded in mystery as oil companies seldom offer up their additive formulations. But regarding pressure discussions, engine oil quality has an impact, as viscosity effects pressure. It's not all about synthetic vs dino oil, but it does seem to end up that way. Why?
1. Synthetic oils don't depend on viscosity additives much if any at all. Viscosity stays stable over oil usage lifetime, where dino oils require additives and degrade and loose viscosity flexibility with use as these dissipate. If viscosity matters, synthetics are plainly superior over their useful lifetime.
2. The more additives in an oil, the less oil there is there to lubricate. Multi-V Dino oil depends on large amounts of additives to maintain its very nature. Less % true oil means less lubrication.
3. Superior oil film shear strength is THE defense against engine wear. It's what engine oil does 1st and foremost, followed by heat removal. Yes, pressure moves the oil, flow rate cools the engine, but the oil with the highest film strength keeps metal surfaces apart best, cold or hot, high or low rpm....and wins in fighting engine wear.
5. Accumulating deposits, particles, acids, water, etc. in any oil eventually will degrade oil's ability to do it's work. As it's so difficult to judge this, error on the conservative side of oil change intervals is the smart choice. And do it with an oil that has designed in, not added on, superior and stable properties from start to finish.
Sum it up and the more additives in an oil (typically dino oil), the quicker it looses it advertised properties for wear, viscosity, film strength, etc., due to use. I know only one (maybe two) oils that highlight these factors specific to the needs of a rotary engine, and they're both synthetic. I would offer that we could debate the theory of oil...viscosity, flow, pressure [thread topic], film strength, etc., forever, and perhaps reach conclusions....but all of that it pretty much a theoretical discussion of the dynamic properties of viscous fluids.
It's the quality that counts, start to finish. If the quality of the product flowing though the engine is subpar, or doesn't have originally or is depleted of the correct additives, is dirty with suspended particles and chemical compounds, then all the pressure or flow possible isn't going to stop wear in the engine.
This factor of basic importance is one shrouded in mystery as oil companies seldom offer up their additive formulations. But regarding pressure discussions, engine oil quality has an impact, as viscosity effects pressure. It's not all about synthetic vs dino oil, but it does seem to end up that way. Why?
1. Synthetic oils don't depend on viscosity additives much if any at all. Viscosity stays stable over oil usage lifetime, where dino oils require additives and degrade and loose viscosity flexibility with use as these dissipate. If viscosity matters, synthetics are plainly superior over their useful lifetime.
2. The more additives in an oil, the less oil there is there to lubricate. Multi-V Dino oil depends on large amounts of additives to maintain its very nature. Less % true oil means less lubrication.
3. Superior oil film shear strength is THE defense against engine wear. It's what engine oil does 1st and foremost, followed by heat removal. Yes, pressure moves the oil, flow rate cools the engine, but the oil with the highest film strength keeps metal surfaces apart best, cold or hot, high or low rpm....and wins in fighting engine wear.
5. Accumulating deposits, particles, acids, water, etc. in any oil eventually will degrade oil's ability to do it's work. As it's so difficult to judge this, error on the conservative side of oil change intervals is the smart choice. And do it with an oil that has designed in, not added on, superior and stable properties from start to finish.
Sum it up and the more additives in an oil (typically dino oil), the quicker it looses it advertised properties for wear, viscosity, film strength, etc., due to use. I know only one (maybe two) oils that highlight these factors specific to the needs of a rotary engine, and they're both synthetic. I would offer that we could debate the theory of oil...viscosity, flow, pressure [thread topic], film strength, etc., forever, and perhaps reach conclusions....but all of that it pretty much a theoretical discussion of the dynamic properties of viscous fluids.
It's the quality that counts, start to finish. If the quality of the product flowing though the engine is subpar, or doesn't have originally or is depleted of the correct additives, is dirty with suspended particles and chemical compounds, then all the pressure or flow possible isn't going to stop wear in the engine.
10-12-2009, 08:50 AM
#217
If I live in places like Florida or AZ or Hawaii
That too
Thats one thing.
but the biggest reason is that I dont have a reading/understanding problem(disability?). unlike some stubborn people in this forum, at least I understand "recommended != required."
and I just love seeing people who cry out loud all the time about "omg Mazda recommend you to use #####,"
but the next minute he/she took his car to the local Auto shop to do whatever it needs to be done.
for some reason he/she can see the part he likes in the manual, but then he/she totally misses out the part that Mazda recommend all work to be perform @ a Mazda dealer.
Funny
That too
but the biggest reason is that I dont have a reading/understanding problem(disability?). unlike some stubborn people in this forum, at least I understand "recommended != required."
and I just love seeing people who cry out loud all the time about "omg Mazda recommend you to use #####,"
but the next minute he/she took his car to the local Auto shop to do whatever it needs to be done.
for some reason he/she can see the part he likes in the manual, but then he/she totally misses out the part that Mazda recommend all work to be perform @ a Mazda dealer.
Funny
Last edited by nycgps; 10-12-2009 at 08:56 AM.
10-15-2009, 01:42 AM
#218
Ayrton Senna Forever
My 3c worth. After reading thru this entire thread, it's obvious there's a lot of info info here sort of distilled from so many threads before. Still, much here is based on speculation or 'assumptions' about oil and how it works, plus a little bit of comment based on actual experience and tear down. But strangely as far as I saw only a couple people mention (or comment on) the importance of the intrinsic quality of an oil to start off with.
This factor of basic importance is one shrouded in mystery as oil companies seldom offer up their additive formulations. But regarding pressure discussions, engine oil quality has an impact, as viscosity effects pressure. It's not all about synthetic vs dino oil, but it does seem to end up that way. Why?
1. Synthetic oils don't depend on viscosity additives much if any at all. Viscosity stays stable over oil usage lifetime, where dino oils require additives and degrade and loose viscosity flexibility with use as these dissipate. If viscosity matters, synthetics are plainly superior over their useful lifetime.
2. The more additives in an oil, the less oil there is there to lubricate. Multi-V Dino oil depends on large amounts of additives to maintain its very nature. Less % true oil means less lubrication.
3. Superior oil film shear strength is THE defense against engine wear. It's what engine oil does 1st and foremost, followed by heat removal. Yes, pressure moves the oil, flow rate cools the engine, but the oil with the highest film strength keeps metal surfaces apart best, cold or hot, high or low rpm....and wins in fighting engine wear.
5. Accumulating deposits, particles, acids, water, etc. in any oil eventually will degrade oil's ability to do it's work. As it's so difficult to judge this, error on the conservative side of oil change intervals is the smart choice. And do it with an oil that has designed in, not added on, superior and stable properties from start to finish.
Sum it up and the more additives in an oil (typically dino oil), the quicker it looses it advertised properties for wear, viscosity, film strength, etc., due to use. I know only one (maybe two) oils that highlight these factors specific to the needs of a rotary engine, and they're both synthetic. I would offer that we could debate the theory of oil...viscosity, flow, pressure [thread topic], film strength, etc., forever, and perhaps reach conclusions....but all of that it pretty much a theoretical discussion of the dynamic properties of viscous fluids.
It's the quality that counts, start to finish. If the quality of the product flowing though the engine is subpar, or doesn't have originally or is depleted of the correct additives, is dirty with suspended particles and chemical compounds, then all the pressure or flow possible isn't going to stop wear in the engine.
This factor of basic importance is one shrouded in mystery as oil companies seldom offer up their additive formulations. But regarding pressure discussions, engine oil quality has an impact, as viscosity effects pressure. It's not all about synthetic vs dino oil, but it does seem to end up that way. Why?
1. Synthetic oils don't depend on viscosity additives much if any at all. Viscosity stays stable over oil usage lifetime, where dino oils require additives and degrade and loose viscosity flexibility with use as these dissipate. If viscosity matters, synthetics are plainly superior over their useful lifetime.
2. The more additives in an oil, the less oil there is there to lubricate. Multi-V Dino oil depends on large amounts of additives to maintain its very nature. Less % true oil means less lubrication.
3. Superior oil film shear strength is THE defense against engine wear. It's what engine oil does 1st and foremost, followed by heat removal. Yes, pressure moves the oil, flow rate cools the engine, but the oil with the highest film strength keeps metal surfaces apart best, cold or hot, high or low rpm....and wins in fighting engine wear.
5. Accumulating deposits, particles, acids, water, etc. in any oil eventually will degrade oil's ability to do it's work. As it's so difficult to judge this, error on the conservative side of oil change intervals is the smart choice. And do it with an oil that has designed in, not added on, superior and stable properties from start to finish.
Sum it up and the more additives in an oil (typically dino oil), the quicker it looses it advertised properties for wear, viscosity, film strength, etc., due to use. I know only one (maybe two) oils that highlight these factors specific to the needs of a rotary engine, and they're both synthetic. I would offer that we could debate the theory of oil...viscosity, flow, pressure [thread topic], film strength, etc., forever, and perhaps reach conclusions....but all of that it pretty much a theoretical discussion of the dynamic properties of viscous fluids.
It's the quality that counts, start to finish. If the quality of the product flowing though the engine is subpar, or doesn't have originally or is depleted of the correct additives, is dirty with suspended particles and chemical compounds, then all the pressure or flow possible isn't going to stop wear in the engine.
..and we have to know that a 5w-30 full syn oil comes from 30w oil, but a 5w-30 dino based oil comes from 5w oil, so if a full syn 5w-30 loses its additives it will stay in the 30w range, but if a 5w-30 dino based loses its additives, it will close to the 5w range, and will be too thin at working temp.
10-15-2009, 11:33 AM
#219
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Someone needs to install an oil temperature gauge in the oil pan. Temps shouldn't exceed 250*F there which is pretty damned hot. Any reference cSt at 100*C will be even thinner at 250*F. This is actually the most relevant place to monitor as it tells us what the oil is getting up to where it counts.
10-15-2009, 11:58 AM
#220
SARX Legend
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Someone needs to install an oil temperature gauge in the oil pan. Temps shouldn't exceed 250*F there which is pretty damned hot. Any reference cSt at 100*C will be even thinner at 250*F. This is actually the most relevant place to monitor as it tells us what the oil is getting up to where it counts.
I am seriously considering this. Just don't know of I wanna do it on the stock pan or an aftermarket one.
10-15-2009, 11:59 AM
#221
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Someone needs to install an oil temperature gauge in the oil pan. Temps shouldn't exceed 250*F there which is pretty damned hot. Any reference cSt at 100*C will be even thinner at 250*F. This is actually the most relevant place to monitor as it tells us what the oil is getting up to where it counts.
10-15-2009, 02:10 PM
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Someone needs to install an oil temperature gauge in the oil pan. Temps shouldn't exceed 250*F there which is pretty damned hot. Any reference cSt at 100*C will be even thinner at 250*F. This is actually the most relevant place to monitor as it tells us what the oil is getting up to where it counts.
Doesn't the oil head to the coolers from the oil pan before doing it's lubrication/cooling duties? Or are you suggesting monitoring the highest oil temps to determine if it may be breaking down (does it break down with heat, or only contaminants?)
10-15-2009, 02:31 PM
#224
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The highest temps are what is important. The oil can only absorb so much heat going through the engine. If the oil in the pan averaged 250*F but the oil entering the engine averaged 210*F, we can see that the coolers can dissipate 40*F worth of heat. More importantly the highest temps of the oils can tell us how thin our oil is really getting where it counts. It's not hard to see that if we increased our oil cooling ability so that it could enter the engine at 200*F, the temp in the pan should go down a corresponding amount. To me what matters is max oil temps in the engine. What it is going in shouldn't really matter as long as it only gets so hot max. The oil should not be allowed to exceed 250*F max. That's an arbitrary number of course as it can go hotter but understanding that it will also break down faster. That is the number that Mazdacomp recommends as a max as measured in the pan.